This post goes into specifics on Django, but the broader points apply no matter what your tech stack. I’m relieved to find out that The Session is using the tripartite identity pattern (although Huffduffer, alas, isn’t):

What we really want in terms of identifying users is some combination of:

System-level identifier, suitable for use as a target of foreign keys in our database

Login identifier, suitable for use in performing a credential check

Public identity, suitable for displaying to other users

Many systems ask the username to fulfill all three of these roles, which is probably wrong.

I understand how bloated and non-reusable code can get when a dozen people who don’t talk to each other work on it over a period of years. I don’t believe the problem is the principle of semantic markup or the cascade in CSS. I believe the problem is a dozen people working on something without talking to each other.